A simplified diagnostic test for ambulatory screening of peripheral diabetic neuropathy

The reliability and reproducibility of Michigan Neuropathy Screening Instrument (MNSI), a recently proposed simple test for ambulatory screening of peripheral diabetic neuropathy (PDN), was evaluated on 80 diabetic patients. MNSI was carried out by two diabetologists and repeated after a week. It consisted of the sum of scores varying from 0 to 1 for each abnormality revealed in foot appearance, achilles reflexes presence and vibratory threshold (VPT) by tuning fork (maximum score = 8). Then patients had to go to neurologist for PDN diagnosis by a quantitative neurological examination and electrophysiological evaluation, the so named Michigan Diabetic Neuropathy Score (MDNS) and the results compared with MNSI score according to one of the two observers. The inter-observer reproducibility of MNSI was 88.75% the within observer reproducibility was 95 and 94%, respectively, for each observer with good correlation between the two measurements (P < 0.001). The MNSI score of 2.5 as a cut-off appeared to be reliable for ambulatory screening of suspected PDN (false positive and false negative = 2.5%; specificity and sensitivity = 75% and 78.6%, respectively). In conclusion MNSI by using 2.5 score as cut-off may be considered a rapid, simple, reproducible and reliable test for rapid ambulatory screening of PDN from the diabetologists.